Stack with Linked List 3

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct Student {
    char name[50];
    int reg;
    double cgpa;
    int semester;
    int year;
    int isRegular; // irregular = 0, regular = 1
    struct Student* next;
};

struct Student* head = NULL;

void addNewStudent(const char* Name, int reg_no, double gpa, int sem, int years, int reg) {
    struct Student* ptr = (struct Student*)malloc(sizeof(struct Student));
    if (ptr == NULL) {
        printf("Memory allocation failed\n");
        exit(1);
    }
    strcpy(ptr->name, Name);
    ptr->reg = reg_no;
    ptr->cgpa = gpa;
    ptr->semester = sem;
    ptr->year = years;
    ptr->isRegular = reg;
    ptr->next = NULL;

    if (head == NULL || head->cgpa < ptr->cgpa) {
        ptr->next = head;
        head = ptr;
    } else {
        struct Student* temp = head;
        while (temp->next != NULL && ptr->cgpa < temp->next->cgpa) {
            temp = temp->next;
        }
        ptr->next = temp->next;
        temp->next = ptr;
    }
    printf("New Student is Added - %s\n", ptr->name);
}

void delStudent(int reg_no) {
    struct Student* temp = head;
    struct Student* prev = NULL;

    while (temp != NULL) {
        if (temp->reg == reg_no) {
            if (prev == NULL) { // Deleting head node
                head = temp->next;
            } else {
                prev->next = temp->next;
            }
            printf("Student Record is Removed - %s\n", temp->name);
            free(temp);
            return;
        }
        prev = temp;
        temp = temp->next;
    }
    printf("Student Record with reg number %d not found\n", reg_no);
}

void displayAllStudent() {
    struct Student* p = head;
    while (p != NULL) {
        printf("%d_%s_%.2f_%d-%d_", p->reg, p->name, p->cgpa, p->year, p->semester);
        if (p->isRegular)
            printf("Regular\n");
        else
            printf("Irregular\n");
        p = p->next;
    }
}

struct Student* awardStack = NULL;

void pushAwardee(struct Student* student) {
    struct Student* newAwardee = (struct Student*)malloc(sizeof(struct Student));
    if (newAwardee == NULL) {
        printf("Memory allocation failed\n");
        exit(1);
    }
    *newAwardee = *student;
    newAwardee->next = awardStack;
    awardStack = newAwardee;
    printf("Selected Awardee Enlisted - %s\n", student->name);
}

void popAwardee() {
    if (awardStack == NULL) {
        printf("No awardee to remove\n");
        return;
    }
    struct Student* temp = awardStack;
    awardStack = awardStack->next;
    printf("Awardee Removed - %s\n", temp->name);
    free(temp);
}

void displayAllAwardee() {
    struct Student* temp = awardStack;
    while (temp != NULL) {
        printf("%d_%s_%.2f_%d-%d_", temp->reg, temp->name, temp->cgpa, temp->year, temp->semester);
        if (temp->isRegular)
            printf("Regular\n");
        else
            printf("Irregular\n");
        temp = temp->next;
    }
}

struct Student* findStudentByName(const char* name) {
    struct Student* p = head;
    while (p != NULL) {
        if (strcmp(p->name, name) == 0) {
            return p;
        }
        p = p->next;
    }
    return NULL;
}

// Circular queue for tokens
struct TokenQueue {
    struct Student* student;
    struct TokenQueue* next;
};

struct TokenQueue* front = NULL;
struct TokenQueue* rear = NULL;

void newToken(struct Student* student) {
    struct TokenQueue* newTokenNode = (struct TokenQueue*)malloc(sizeof(struct TokenQueue));
    if (newTokenNode == NULL) {
        printf("Memory allocation failed\n");
        exit(1);
    }
    newTokenNode->student = student;
    if (front == NULL) {
        front = rear = newTokenNode;
        newTokenNode->next = front;
    } else {
        rear->next = newTokenNode;
        rear = newTokenNode;
        rear->next = front;
    }
    printf("New Token Created - %s\n", student->name);
}

void serveToken() {
    if (front == NULL) {
        printf("No tokens to serve\n");
        return;
    }
    struct TokenQueue* temp = front;
    if (front == rear) {
        front = rear = NULL;
    } else {
        front = front->next;
        rear->next = front;
    }
    printf("Token Served - %s\n", temp->student->name);
    free(temp);
}

void displayQueue() {
    if (front == NULL) {
        printf("Queue is empty\n");
        return;
    }
    struct TokenQueue* temp = front;
    do {
        printf("%d_%s_%.2f_%d-%d_", temp->student->reg, temp->student->name, temp->student->cgpa, temp->student->year, temp->student->semester);
        if (temp->student->isRegular)
            printf("Regular\n");
        else
            printf("Irregular\n");
        temp = temp->next;
    } while (temp != front);
}

int main() {
    addNewStudent("Monica", 22201999, 3.50, 1, 2, 1);
    addNewStudent("Ross", 22201000, 3.92, 1, 2, 1);
    addNewStudent("Chandler", 18201000, 4.0, 1, 3, 1);
    addNewStudent("Janice", 21201089, 2.52, 1, 2, 0);
    addNewStudent("Joey", 20201979, 2.88, 1, 2, 0);
    addNewStudent("Gunther", 19201000, 4.0, 2, 3, 0);

    printf("\n");
    delStudent(21201089);
    printf("\n");
    displayAllStudent();
    printf("\n");

    // Push "Monica", "Ross", and "Chandler" to the awardee stack
    struct Student* student;

    student = findStudentByName("Monica");
    if (student != NULL) pushAwardee(student);

    student = findStudentByName("Ross");
    if (student != NULL) pushAwardee(student);

    student = findStudentByName("Chandler");
    if (student != NULL) pushAwardee(student);

    printf("\nAll Awardees:\n");
    displayAllAwardee();

    printf("\n");

    // Adding tokens for food distribution
    student = findStudentByName("Monica");
    if (student != NULL) newToken(student);

    student = findStudentByName("Ross");
    if (student != NULL) newToken(student);

    student = findStudentByName("Chandler");
    if (student != NULL) newToken(student);

    student = findStudentByName("Gunther");
    if (student != NULL) newToken(student);

    student = findStudentByName("Joey");
    if (student != NULL) newToken(student);

    printf("\nQueue Display:\n");
    displayQueue();

    printf("\n");

    // Serving tokens
    serveToken();
    serveToken();

    printf("\nQueue Display after serving two tokens:\n");
    displayQueue();

    return 0;
}